A dosimeter is a device generally used to measure exposure to a hazardous environment, particularly when the hazardous impact is cumulative over long intervals of time. With regard to noise, for example, a noise dosimeter is a device which incorporates a sound level measurement subsystem and a methodology for integrating or accumulating the sound level over time. ANSI S1.25-1991 is the current American National Standard Specification for Personal Noise Dosimeters, a comprehensive document that describes how a standard noise dosimeter should function. A calculable result of noise dose measurement over time may be what is known as the “equivalent continuous sound level”, denoted as Leq. A noise dose might also be expressed as a percentage of “criterion exposure.” The “criterion sound level”, for example 85 dB, is the level of sound, which having been applied continuously for a duration equal to the “criterion time,” typically 8 hours, results in a 100% criterion exposure. These calculations are completely specified in the standard and are well known in the industry.
Many environments expose individuals to excessively loud sounds. These loud sounds may occur at, for example, music concerts, industrial manufacturing environments, construction and environments involving the use of heavy machinery, etc. The US government regulates, through OSHA (Occupational Safety and Health Administration), noise exposure levels in work environments. There are many noise dosimeters on the market, which are used to monitor noise in the work environment. These regulations and devices represent a level of protection for many American workers.
There are other environments, in which loud noises exist, that are far less regulated. Therefore, the development of a low cost noise dosimeter is needed to provide individuals or organizations with an inexpensive and simple means of monitoring noise exposure.
Existing devices used for measuring noise exposure have several problems. For example, existing devices tend to be too complicated for operation by the average user, and they are generally too expensive for the average user, in that they are primarily designed for use by technically trained personnel in an industrial environment, which is reflected in their cost and complexity. Further, existing devices can be inappropriate to wear in most social occasions and situations and may also have insufficient accuracy, precision and/or flexibility. Additionally, existing devices are designed for use over an extended period of time, e.g. an entire workday, and cannot rapidly predict noise exposure in situations where the listener is exposed to sound that is of a similar nature for an extended period, such as a music concert.
In addition to sound or noise dosimeters, other types of dosimeters include radiation dosimeters, which measure exposure to ionizing radiation such as x-rays, ultraviolet light, or electromagnetic fields, and chemical vapor dosimeters. X-ray radiation cannot be detected by the senses, so workers who may be exposed to such radiation are often required to wear dosimeters so their employers can keep a record of their exposure and verify that it is below legally prescribed limits.
Further limitations and disadvantages of conventional and traditional approaches will be apparent to one of skill in the art through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.